Birkenfeld said he is "ready, willing and able" to assist in the government's prosecution of the UBS clients that sought to avoid taxes. The WSJ Law Blog has the full report here.

He requested the court postpone and reconsider his prison term; in addition to wanting to further cooperate, he claimed his prior cooperation has been mischaracterized and that he was not provided the legal safeguards required for a whistleblower under Swiss law.

Though the government admitted they had basically no case without Birkenfeld, he was still sentenced to 40 months in prison, in part because prosecutors felt he was dishonest about his participation in the fraud and because he did not provide information about his biggest client, California billionaire Igor Olenicoff.

Birkenfeld's story will be watched by would-be whistleblower for years to come -- after he gets out of jail (he's scheduled to report January 8), he's hoping to recover "several billion dollars" for helping authorities bring down the tax evasion scheme.